Among the methods for affecting formations and bottom-hole zone of oil wells with the aim to increase their productivity, acoustical methods ensuring oil inflow from the production formation to the development area are widely spread.
Known methods are classified by an acoustical impact frequency band. Low-frequency methods applied for production formation impact increase the formation pressure and bring into development stagnant areas of the formation; however, the above-mentioned impact is only effective in case if impact frequencies are close to resonant frequencies defined by geophysical properties of the said formation (e.g., U.S. Pat. No. 6,899,175, 31 May 2005).
Ultrasonic methods applied for impacting a well production area at frequencies of 10-25 kHz change physicochemical properties of the impacted formation and lead to, e.g., a reduced oil viscosity (U.S. Pat. No. 5,109,922 of May 5, 1992), which, in its turn, facilitates the cleaning of pore space, however, the field of application of ultrasonic methods is limited to the well's nearest area.
Another known method of oil recovery enhancement is implemented through an acoustic impact on the formation in a broadened high-frequency span as well as in a low-frequency span; this ensures excitation of both adjacent production formations and those remote from the well (RF patent No. 2162519 of Jan. 27, 2001).
The method that calls for lowering a vibroacoustic downhole emitter in a well and performing a consecutive high-frequency and low-frequency impacts on the formation bottomhole area (RF patent No. 2267601) is the most similar to the claimed method. This method provides oil recovery increase due to an increased oil inflow.
However, the issue of a direct impact on a local fluid flow velocity in the oil formation's pore space remains unresolved.